alphabetic character set
Technical computing term for a set of alphabetic characters, as opposed to numeric or symbolic sets.
This program recognizes only alphabetic character sets.
文字集合 is a broader term for any character set, while 欧字集合 specifically refers to alphabetic (European) character sets.
Compound of 欧字 (alphabetic character) and 集合 (set). The term is a technical coinage in computing.